(1) Field of the Invention
Reducing the diameter and weight of confined detonating fuse, while retaining or improving the confining characteristics. Current technology uses "E" glass for confinement manufactured by Owens Corning and conforming to U.S. Military Specification M/L-Y-1140. To achieve confinement, as many as twelve overbraid layers of "E" glass are used in conjunction with a plastic extrusion covering for abrasion resistance and environmental protection.
(2) Description of the Prior Art
______________________________________ Great Britain 847,743 West Germany 1,248,526 West Germany 1,124,413 West Germany 1,070,535 SMITH 3,881,420 LANGRISH-SMITH 3,867,884 GRAYSON 3,731,626 HELFGENI 3,730,097 PRIOR 3,730,096 CALDER 3,726,216 PRIOR 3,382,802 NODDIN 3,311,056 KELLY 3,260,201 HICKS 3,125,024 SMITH 3,155,038 GRANDY 3,027,839 ANDREW 2,982,210 ANDREW 2,923,239 DOLAN 2,892,475 JOHNSON 2,380,312 ______________________________________
The above-listed prior art suggests a variety of coverings for the mild detonating fuse, but is not consistently directed to actual confinement of the MDF and does not suggest the particular combination of coverings claimed by applicant.
Great Britain Pat. No. 847,743 uses loosely wound cotton yarn to provide spaces for flame/gas propagation and is not intended to confine anything.
West German Pat. No. 1,248,526 employs a single fiber and wire covering for the explosive core to obtain confinement. West German Pat. No. 1,124,413 uses fiberglass to confine "black powder" but does not confine detonating materials. West German Pat. No. 1,070,535 is related to the use of a dipicryl sulfone which is reinforced so as to be water proof; however, there is no suggestion of confinement.
Smith U.S. Pat. No. 3,881,421 is a smoke cord, using yarn 12, 14 to hold the product together. The yarn is not confining nor is the cord detonating. The smoke cord is deflagrating, that is, burning. Langrish uses textile wrappings for waterproofing detonating cord. The product is manufactured by Ensign-Bickford under the trademark PRIMACORD and is not intended to confine but rather explodes. Grayson is not concerned with confinement, but uses filaments to prevent stretching of the cord. Helfgeni uses a woven or spun overbraid to position or hold the items together, but does not claim to perform confinement. He expects the cord to rupture. Prior U.S. Pat. No. 3,730,096 employs a spun sheath as a strengthener for manufacturing and handling purposes, but has nothing to do with confinement. Calder is specifically constructed to ensure cross propagation and non-confinement. The multi-layer covering construction is designed for increased handling strength and moisture exclusion, but is of generally weak elements, for example, paper, wax, textile. Prior U.S. Pat. No. 3,382,802 uses metal and/or fiberglass coverings to replace the metal sheath normally used around small cord detonating materials to give the core the necessary confinement during detonation, thus providing a stable detonation velocity and adequate handling strength. There is no reference to confinement after detonation.
Noddin uses a tough flexible outer covering to absorb the detonation and expand to contain the gas and by-products. Kelly is without intent to totally confine. He uses longitudinal spiral windings to provide core structure and handling strength and includes a foam outer covering to allow breathing and to exclude moisture, oil, etc. The core consists of black powder deflagrating material. It is submitted that a detonating material would disintegrate the Kelly cover. Hicks increases confinement of the explosive by an increase in the explosive area per unit length, thus reducing detonation velocity, it is submitted to the point of instability.
Smith U.S. Pat. No. 3,155,038 concerns PRIMACORD wherein a textile sheath is used to hold the explosive together without confinement, the intention being that it must not confine (column 1, line 16, "the ability to initiate itself by lap connection or a knot connection").
Grandy U.S. Pat. No. 3,027,839 concerns black powder which is not a detonation material. He uses internal space which collapses and increases free volume.
Andrew U.S. Pat. No. 2,982,210 uses small core load metal sheath covered explosive to reduce brisance and noise. Reinforcing is employed to guard against longitudinal stress and to protect the metal sheath against physical damage. It is submitted that in constructions of above one grain per foot explosive, the construction will not confine.
Andrew U.S. Pat. No. 2,923,239 uses fiberglass, cotton, linen, rayon, nylon or wire to withstand deflagration pressure. The configuration specifically excludes detonating material (column 3, line 36) "in general conventional deflagrating explosives will perform satisfactorily while detonating high explosives are not suitable".
Dolan U.S. Pat. No. 2,891,475 uses a flame to the extent that it will not ignite a flammable substance, namely a thermoplastic sheath impregnated with flame suppressing material.
Johnson U.S. Pat. No. 2,380,312 provides a cord, having higher handling and general service strength by wire braiding without reference to an improvement in confinement strength.